This invention relates to a transportable electrical switching assembly of the type which includes various electrical switching components mounted on a trailer so as to be transportable on highways within acceptable highway dimensions to a temporary use location.
Various types of switching and transformer assemblies have typically been provided on highway trailers for transportation to a required use location and examples are manufactured by Pauwels Contracting Inc. of Winnipeg, Manitoba, Canada for this purpose. These units are referred to as xe2x80x98mobilesxe2x80x99 within the electrical utility industry. Typically such devices include a transformer mounted on a lower section of the trailer, a low voltage section with switches and circuit interrupters at one end and a high voltage section with switches and circuit interrupters at the opposed end. However other configurations and other combinations of components are often mounted for transportation in this manner.
One component which has recently become available is a switching unit known under the trademark of xe2x80x9ctransrupterxe2x80x9d which is a tower manufactured by the S and C Electric Company. This has a height of the order of 10 (ten) feet and must be located in vertical orientation so that, while it is eminently suitable from an operational and total weight point of view for a mobile unit of the above type, it has not been possible to be used in view of its height on the trailer being well above the legal transportation height. Overall compactness of mobiles is also a major or even critical factor.
It is one object of the present invention to provide an improved mobile electrical switching assembly.
According to the invention therefore there is provided a mobile electrical switching assembly comprising:
a trailer having a trailer bed, ground wheels for supporting the trailer bed and a hitch connection for towing of the trailer along highways by a tractor vehicle;
three phase electrical switching components mounted on the trailer bed for transportation thereby to a required location for temporary connection to a high voltage electrical supply;
the electrical switching components including a circuit interrupter coordinated for three phase electrical supply including three individual towers arranged to operate on a respective phase and arranged in use to be mounted vertically at transversely spaced positions on the trailer;
each tower being mounted on a respective support carried on the trailer so as to support the tower in operation and in transportation;
each support including a bracket attached to a bottom of the tower with the bracket mounted for pivotal movement about a horizontal axis for movement of the tower about the axis from a vertical operating position to an inclined transport position.
Preferably each support is arranged such that in the transport position the tower is inclined so that it extends from the bracket upwardly and along the trailer.
Preferably each support is arranged such that the tower is inclined at an angle of the order of 45 degrees such that its upper end in the transport position is at a height less than 13.5 feet from the ground. The circuit interrupter is typically mounted over the rear axles of the trailer so that the bottom of the circuit interrupter is at 5-6 feet above ground level.
Preferably there is provided a brace member arranged to extend from the trailer to a position on the tower spaced from the bracket for bracing the tower in the inclined transport position.
Preferably the upper end of the brace connects to a bracket extending along the tower and connected thereto at two spaced collars thereon, where the bracket is removed during operation.
Preferably the trailer includes a lower bed section and a raised section and wherein the towers are mounted on the raised section. Although many configurations are possible.
Preferably the brackets are rotated about the horizontal axis by a manually operable turn-buckle which provides a simple inexpensive operation for the infrequent use necessary for movement between transport and operating positions. However suitable powered components can also be provided.
In most cases, the electrical switching components include a transformer but other mobile switching assemblies of various different operations may use the same tower type circuit interrupters and the mounting described above.
Preferably the towers are arranged in a row across the trailer and the bracket of each is arranged for pivotal movement about a common transverse axis so that, when inclined in the transport position, the towers lie in a common plane inclined to the trailer.
Preferably the two outer towers are mounted such that, when in the vertical operating position, their position on the trailer can be moved outwardly of the trailer so as to increase the spacing of each of the outer towers from the center tower in the operating position. Typical phase spacing for these components can range from 7-9 feet. Typical trailer width is 8.5 feet.
Preferably the bracket of each of the two outer towers is mounted on a respective tower arm mounted for rotation about a vertical axis on a respective support or post such that rotation of the tower arm about the vertical axis moves the bracket of the respective circuit interrupter outwardly relative to the trailer.
Preferably each tower is associated with a respective one of three further components, such as lightning arresters, to which it is electrically connected and which is mounted in vertical orientation parallel to the respective tower on a bracket carried on the respective post.
Preferably each further component is mounted on a component arm separate from the tower arm of the respective tower and carried on the respective post. The preferred mounting for the elements is defined by the post and two collars since this is simple and mechanically effective, but other mounting arrangements can be employed within the knowledge of one skilled in this art.
Preferably at least the two outer component arms are pivotal on a collar about the respective vertical axis on the respective post for increasing the spacing therebetween in the operating position thereof.
Preferably each of the component arms is pivotal about the respective vertical axis on the respective support for moving the further component out of alignment with the respective tower when the tower is moved to the inclined transport position. This allows the tower to be located at a minimum spacing from the further component which would otherwise cause the tower to interfere with the further component when inclined to the transport position, by moving the, further component to one side on its arm. The center component is also moved to one side and thus is also mounted on an arm, although the arm may be of reduced length relative to the arms of the outer components.
In one example each of the further components comprises a lightning arrester, although other components may be used in a similar configuration with the towers.